An interconnect fabric provides for communication among a set of nodes in a network. Communications originate within the network at a source node and terminate at a terminal node. Thus, a wide variety of networks may be viewed as a set of source nodes that communicate with a set of terminal nodes via an interconnect fabric. For example, a storage area network may be arranged as a set of computers as source nodes which are connected to a set of storage devices as terminal nodes via an interconnect fabric that includes communication links and devices such as hubs, routers, switches, etc. Devices such as hubs, routers, switches, etc., are hereinafter referred to as interconnect devices. Depending on the circumstances, a node may assume the role of source node with respect to some communications and of terminal node for other communications.
The communication requirements of an interconnect fabric may be characterized in terms of a set of flow requirements. A typical set of flow requirements specifies the required communication bandwidth from each source node to each terminal node. The design of an interconnect fabric usually involves selecting the appropriate arrangement of physical communication links and interconnect devices and related components that will meet the flow requirements.
An interconnect fabric that meets the minimum flow requirements under ideal conditions will not necessarily meet the flow requirements under other conditions, such as in the event of a failure of a communication link, interconnect device or related component. Therefore, network designers typically address these reliability considerations by building in excess capacity or redundancy to help meet flow requirements under adverse conditions. Prior techniques are largely ad hoc and, thus, tend to be time-consuming, error-prone and may result in an over-provisioned interconnect fabric.